Organic polymer, conducting organic polymer, production methods and uses of the same

ABSTRACT

This invention relates to a conducting organic polymer formed by doping an organic polymer with a protonic acid having a dissociation constant value pKa of less than 4.8, wherein the organic polymer has, as the main repeating unit, a compound represented by the general formula: ##STR1## wherein, m and n, respectively, show the molar fraction of the quinonediimine structural unit and phenylenediamine structural unit in the repeating unit, and 0&lt;m&lt;1, 0&lt;n&lt;1, and m+n=1; and the organic polymer is soluble in an organic solvent in the undoped state, and has an intrinsic viscosity  η! of more than 0.4 dl/g measured in N-methyl-2-pyrrolidone at 30° C. This invention also relates to a film formed of the conducting organic polymer and a conducting organic polymer composition.

CROSS REFERENCE TO RELATED APPLICATIONS

This is a Continuation of Application Ser. No. 08/087,907 filed on Jul.9, 1993 (abandoned) which is a Divisional of prior application Ser. No.07/413,502 filed Sep. 27, 1989, and now U.S. Pat. No. 5,264,552.

FIELD OF THE INVENTION

This invention relates to a novel high-molecular-weight organic polymer,a conducting organic polymer, the methods for producing them, and theuses of the same, and more particularly, a high-molecular-weight organicpolymer having free-standing film forming properties and obtained by thechemical oxidative polymerization of aniline, a conducting organicpolymer obtained therefrom, the methods for producing the same, and theuses thereof.

BACKGROUND OF THE INVENTION

The method for producing a conducting organic polymer containing anelectrolytic ion as a dopant, and having electric conductivity of morethan 10⁻⁶ S/cm by chemical oxidative polymerization of aniline with achemical oxidizing agent is already known (U.S. Pat. No. 4,615,829), andfurther, the fact that, in the production of a conducting organicpolymer by use of such chemical oxidative polymerization, an oxidizingagent having the standard electrode potential determined as anelectromotive force in the reduction half cell reaction making thestandard hydrogen electrode as a standard of more than 0.6 V is usedpreferably, is also already described in the official publication ofJapanese Patent Application Laid-Open No. 258831/1986.

However, since the conducting organic polymer is generally insoluble andinfusible, it cannot be formed into a film, and hence, there is a largehindrance for developing useful applications of the conducting organicpolymer. As described in the official publication of Japanese PatentApplication Laid-Open No. 235831/1985 and J. Polymer Sci., Polymer Chem.Ed., 26, 1531 (1988), although a film of the conducting organic polymercan be formed on the electrode, since the film formation surface islimited to the surface of the electrode, it is difficult to obtain afilm of large area, and moreover, since the film formation is effectedby electrolytic oxidation, the production cost is high. Moreover, thisfilm has low strength and is insoluble and infusible.

Therefore, various conversion methods have been proposed, in which anintermediate product soluble in an organic solvent is to be produced,and after making the solution into a film by the casting method, theintermediate product is changed to a conducting polymer by physical orchemical means. However, according to this method, treatment at a hightemperature is required, and the change from the intermediate product toa conducting polymer does not necessarily proceed as showntheoretically, so that the method is not practical also as theproduction method of the conducting organic polymer film, when seen fromthe production side and the side of the physical properties of the filmobtained.

In the field of polypyrrole or polythiophene, a polymer soluble in anorganic solvent is known. The thiophene having a long chain alkyl groupas a substituent and the pyrrole having the alkane sulfonic acid groupas a substituent were subjected to electrochemical oxidativepolymerization to obtain respectively poly-3-alkylthiophene soluble inan organic solvent and poly-pyrrolealkane sulfonic acid soluble inwater. Films of any of these polymers can be obtained from theirsolutions by the casting method. However, this method uses specialmonomers in either case, and in addition, it mutt be subjected toelectrochemical oxidative polymerization, so that the production cost isextremely high.

On the other hand, in the field of chemical oxidative polymerization ofaniline, it is reported, in recent years, that a polyaniline soluble inan organic solvent can be obtained by applying about 1/4 amount ofammonium peroxodisulfate as an oxidizing agent to aniline, to letaniline be subjected to chemical oxidative polymerization. (A. G.MacDiarmid et al., Synthetic Metals, 21, 21 (1987); A. G. MacDiarmid etal., L. Alcacer (ed.), Conducting Polymers, 105-120, D. ReidelPublishing Co., (1987).) However, this polymer is soluble not only inN-methyl-2-pyrrolidone and dimethyl sulfoxide, but also, in 80% aceticacid and 60% formic acid aqueous solution, and its molecular weight islow. It is also described that a free-standing film can be obtained fromthe solutions of the polymer in N-methyl-2-pyrrolidone and dimethylsulfoxide. Further, it is also described that a conducting polymer filmdoped with acetic acid can be obtained from an acetic acid solution, andthis is made as a film undoped with ammonia. However, since the film inthis undoped state has a low molecular weight of polyaniline, itsstrength is low, and it is easily broken by bending, and it is hardlysuitable for practical use.

Also, it is known that polyaniline soluble in tetrahydrofuran can beobtained by oxidizing aniline with ammonium peroxodisulfate (J. Tang etal., Synthetic Metals, 24, 231 (1988)). However, this polymer can beconsidered to have a low molecular weight, since it dissolves intetrahydrofuran.

SUMMARY OF THE INVENTION

The present inventors have eagerly investigated in order to obtain ahigh-molecular-weight organic polymer especially by the chemicaloxidative polymerization of aniline, and as a result, have found outthat the high-molecular-weight polymer of the present invention,although having a molecular weight by far higher than that exhibited bythe conventionally known polyaniline, is soluble in various organicsolvents, and a free-standing film can be easily obtained from itssolution by the casting method. This film is strong and has an excellentflexibility together with a high tensile strength. Further, it has beenfound that a strong, high-molecular-weight, highly conductive organicpolymer film can be obtained by doping such a film with a protonic acid.

The organic polymer according to the present invention is characterizedby having, as the main repeating unit, a compound represented by thegeneral formula: ##STR2## wherein m and n, respectively, show the molarfraction of the quinonediimine structural unit and phenylenediaminestructural unit in the repeating unit, and 0<m<1, 0<n<1, and m+n=1; andthe organic polymer is soluble in an organic solvent in the undopedstate, and has an intrinsic viscosity (η) of more than 0.4 dl/g measuredin N-methyl-2-pyrrolidone at 30° C.

Such an organic polymer according to the present invention has thefeature that, in the ring vibration of the para-substituted benzene inthe laser Raman spectrum obtained by exciting with the light of thewavelength of 457.9 nm, the ratio Ia/Ib of the strength of the Ramanline Ia of the ring stretching vibration appearing at the wave numberhigher than 1,600 cm⁻¹ and the strength of the Raman line Ib of the ringstretching vibration appearing at the wave number lower than 1,600 cm⁻¹is more than 1.0.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the laser Raman spectrum in the case where the organicsolvent soluble aniline oxidative polymer in the undoped state accordingto the present invention was excited with the light of the wavelength of457.9 nm.

FIG. 2 shows the laser Raman spectrum in the case where the heretoforeknown polyaniline was excited with the light of the wavelength of 457.9nm;

FIG. 3 shows the laser Raman spectrum in the case where the same anilineoxidative polymer as that in FIG. 1 has been excited with the light ofvarious different exciting wavelengths;

FIG. 4 shows the electronic spectrum of the N-methyl-2-pyrrolidonesolution of the solvent soluble aniline oxidative polymer in the undopedstate according to the present invention;

FIG. 5 is a graph for showing the molecular weight distribution measuredby means of GPC of the solvent soluble polyaniline according to thepresent invention;

FIG. 6 shows the FT-IR spectrum of the aniline oxidative polymer solublein the undoped state according to the present invention by means of theKBr disk method.

FIG. 7 shows the FT-IR spectrum of the solvent insoluble film obtainedby casting the polymer soluble in the above-described solvent by meansof the KBr method;

FIG. 8 is a diagram of the thermogravimetric analysis of theabove-described soluble polymer and the insoluble polymer film;

FIG. 9 is a diagram for showing the ESR spectrum change in the case ofheating the above-described soluble polymer; and

FIG. 10 shows the reflection spectrum of the near infrared region of thepolymer film in the undoped state and the film obtained by doping itwith perchloric acid.

DETAILED DESCRIPTION OF THE INVENTION

The oxidative polymer of aniline according to the present invention maybe produced by preserving aniline in a solvent, while keeping thetemperature at less than 5° C., or preferably, at a temperature of lessthan 0° C., under the presence of a protonic acid having the aciddissociation constant value pKa of less than 3.0, and by graduallyadding the aqueous solution of an oxidizing agent having the standardelectrode potential of more than 0.6 V, which is determined as theelectromotive force in the reduction half cell reaction standardizedwith a standard hydrogen electrode, for more than two equivalents, orpreferably, 2 to 2.5 equivalents, of the equivalent defined as theamount obtained by dividing one mole of the oxidizing agent with thenumber of electrons required for reducing one molecule of the oxidizingagent to let the oxidative polymer of the aniline doped with theabove-described protonic acid, and subsequently, by undoping thispolymer with a basic substance.

As the above-described oxidizing agent, manganese dioxide, ammoniumperoxodisulfate, hydrogen peroxide, ferric salts, iodic acid salts,etc., are preferably used. Among these, for example, in ammoniumperoxodisulfate and hydrogen peroxide, two electrons participate per onemolecule in both cases, so that the amount in the range of 1 to 1.25 molis generally used.

The protonic acid used in oxidative polymerization of aniline is notespecially limited when the acid dissociation constant value pKa is lessthan 3.0. For example, inorganic acids such as hydrochloric acid,sulfuric acid, nitric acid, perchloric acid, hydrofluoroboric acid,hydrofluorophosphoric acid, hydrofluoric acid, hydroiodic acid, etc.,aromatic sulfonic acids such as benzenesulfonic acid, p-toluenesulfonicacid, etc., alkane sulfonic acids such as methanesulfonic acid,ethanesulfonic acid, etc., phenols such as picric acid, etc., aromaticcarboxylic acids such as m-nitrobenzoic acid, etc., aliphatic carboxylicacids such as dichloroacetic acid, malonic acid, etc., can be used.Further, polymer acids can also be used. Such polymer acids include, forexample, polystyrene sulfonic acid, polyvinyl sulfonic acid, polyallylsulfonic acid, polyvinyl sulfuric acid, etc.

The amount of the protonic acid used depends on the reaction mode of theoxidizing agent used. For example, in the case of manganese dioxide,since the oxidation reaction is shown as:

    MnO.sub.2 +4H.sup.+ +2e.sup.- →Mn.sup.2+ +2H.sub.2 O,

it is necessary to use a protonic acid capable of supplying protons inat least 4 times the mol amount of the manganese dioxide used. Further,in using hydrogen peroxide also, since the oxidation reaction is shownas:

    H.sub.2 O.sub.2 +2H.sup.+ +2e.sup.- →2H.sub.2 O,

it is necessary to use a protonic acid capable of supplying protons inat least two times the mol amount of the hydrogen peroxide used. On theother hand, in the case of ammonium peroxodisulfate, since the oxidationreaction is shown as:

    S.sub.2 O.sub.8.sup.2- +2e.sup.- →2SO.sub.4.sup.2-,

it is not necessary to use protonic acid especially. However, in thepresent invention, it is preferable to use a protonic acid in an equalmol amount to that of the oxidizing agent.

As the solvent for use in the oxidative polymerization of aniline, onewhich dissolves aniline, protonic acid, and the oxidizing agent, and isnot oxidized by the oxidizing agent, may be used. Water is mostpreferably used, but, as needed, alcohols such as methanol, ethanol,etc., nitriles such as acetonitrile, etc., polar solvents such asN-methyl-2-pyrrolidone, dimethyl sulfoxide, etc., ethers such astetrahydrofuran, etc., organic acids such as acetic acid, etc., can beused. Also, the mixed solvent of these organic solvents with water canbe used.

In the method for obtaining the solvent soluble aniline oxidativepolymer according to the present invention, during the reaction,especially while the solution of the oxidizing agent is added to theaniline solution, it is important to preserve the temperature of thereaction mixture always below 5° C. Therefore, it is required that thesolution of the oxidizing agent is gradually added to aniline lest thetemperature of the reaction mixture exceed 5° C.

When the oxidizing agent is rapidly added, the temperature of thereaction mixture rises, even if it is cooled from the outside, to form apolymer having low molecular weight, or to form a solvent insolubleoxidative polymer after the undoping as described in the following.

In particular, in the present invention, it is preferable to keep thereaction temperature below 0° C. because such makes it possible, afterundoping, to obtain the solvent soluble aniline oxidative polymer ofhigh molecular weight having the intrinsic viscosity (η) of more than1.0 dl/g measured at 30° C. in N-methyl-2-pyrrolidone (to be referred toin the same way in the following).

Thus, the oxidative polymer of aniline doped with the protonic acid usedcan be obtained. Since the oxidative polymer of aniline forms a saltwith the protonic acid in the doped state, in a similar manner to thatin many of the conducting organic polymers in the doped state, it is ingeneral insoluble in solvents such as those described in the following.For example, in general, it is well-known that the salts of highmolecular weight amines are only slightly soluble in an organic solvent.However, the conducting organic polymer according to the presentinvention has two important characteristics in comparison with otherconducting organic polymers.

First, the conducting organic polymer according to the present inventiondoes not form a precipitate, and stably dissolves in an aprotic polarorganic solvent depending on the kind of protonic acid used as thedopant, if the concentration is less than several percent by weight. Ingeneral, at the concentration of less than 5% by weight, a solution ofthe conducting organic polymer of such a doping state into an organicsolvent can be obtained.

Here, as the above-described organic solvent, N-methyl-2-pyrrolidone ispreferred. The solution of the conducting organic polymer in such adoped state as described above can readily form a thin film of aconducting organic polymer on a substrate, when the organic solvent isremoved therefrom (after coating it on a suitable substrate).

Secondly, from the conducting organic polymer doped with theabove-described protonic acid and insoluble in an organic solvent, ananiline oxidative polymer soluble in an organic solvent can be obtainedby undoping.

Preferable protonic acids include hydrofluoroboric acid,hydrofluorophosphoric acid, perchloric acid, etc., or any other organicacids having acid dissociation constant pKa values of less than 4.8. Incases when the protonic acid is a mineral acid such as sulfuric acid,hydrochloric acid, nitric acid, etc., the doped polymers are difficultto dissolve in an organic solvent.

The organic acids having the above-described acid dissociation constantpKa value of less than 4.8 contain mono- or polybasic acid such as thatof the aliphatic group, aromatic group, aromatic aliphatic group,alicyclic group, etc., and further such organic acids may have ahydroxyl group, halogen atom, nitro group, cyano group, amino group,etc. Examples of such organic acids include, for example, acetic acid,n-butyric acid, pentadecafluorooctanoic acid, pentafluoroacetic acid,trifluoroacetic acid, trichloroacetic acid, dichloroacetic acid,monofluoroacetic acid, monobromoacetic acid, monochloroacetic acid,cyanoacetic acid, acetylacetic acid, nitroacetic acid, triphenylaceticacid, formic acid, oxalic acid, benzoic acid, m-bromobenzoic acid,p-chlorobenzoic acid, m-chlorobenzoic acid, o-nitrobenzoic acid,2,4-dinitrobenzoic acid, 3,5-dinitrobenzoic acid, picric acid,o-chlorobenzoic acid, p-nitrobenzoic acid, m-nitrobenzoic acid,trimethylbenzoic acid, p-cyanobenzoic acid, m-cyanobenzoic acid, thymolblue, salicylic acid, 5-aminosalicylic acid, o-methoxybenzoic acid,1,6-dinitro-4-chlorophenol, 2,6-dinitrophenol, 2,4-dinitrophenol,p-oxybenzoic acid, bromophenol blue, mandelic acid, phthalic acid,isophthalic acid, maleic acid, fumaric acid, malonic acid, tartaricacid, citric acid, lactic acid, succinic acid, α-alanine, β-alanine,glycine, glycolic acid, thioglycolic acid, ethylenediamine-N,N'-diaceticacid, ethylenediamine-N,N,N',N'-tetraacetic acid, etc.

Also, the organic acid may have sulfonic acid or sulfuric acid group.Such organic acids include, for example, aminonaphtholsulfonic acid,metanilic acid, sulfanilic acid, allylsulfonic acid, laurylsulfuricacid, xylenesulfonic acid, chlorobenzenesulfonic acid, 1-propanesulfonicacid, 1-butanesulfonic acid, 1-hexanesulfonic acid, 1-heptanesulfonicacid, 1-octanesulfonic acid, 1-dodecanesulfonic acid, benzenesulfonicacid, styrenesulfonic acid, p-toluenesulfonic acid, naphthalenesulfonicacid, etc.

Further, the organic acid may be a polymer acid. Such polymer acidsinclude, for example, polyvinylsulfonic acid, polyvinylsulfuric acid,polystyrenesulfonic acid, sulfonated styrene-butadiene copolymer,polyallylsulfonic acid, polymethallylsulfonic acid,poly-2-acrylamide-2-methylpropanesulfonic acid, polyhalogenated acrylicacid, etc.

The fluorine-containing polymer known as Nafione (registered trademarkof DuPont Co., U.S.A.) is preferably used as a polymer acid.

The conducting organic polymer doped with a polymer acid has a differentsolubility depending on the molecular weight of the polymer acid.Usually, the polymer acid having a small molecular weight gives a highsolubility conducting organic polymer in the doped state.

Further, the solution of the conducting organic polymer such asdescribed above can be diluted with other organic solvents as necessary.For example, by adding a diluting agent to a solution in the order ofabout 2% by weight, a diluted solution can be advantageously prepared.As such a diluting agent, those having mutual solubility inN-methyl-2-pyrrolidone are preferable, and therefore, for example,alcohols, ketones, esters, ethers, nitriles, or othernitrogen-containing organic solvents are preferably used.

In particular, for example, aliphatic group alcohols such as methanol,ethanol, propyl alcohol, butyl alcohol, etc., are preferable for thediluting agents. However, glycols such as ethylene glycol can also bepreferably used. Also, acetonitrile and tetrahydrofuran are preferablediluting agents.

Also, according to the present invention, depending on the extent ofdilution, a hydrocarbon solvent such as, for example, n-hexane having nomutual solubility to N-methyl-2-pyrrolidone, can be used as a dilutingagent. Further, it is also possible to dissolve a hydrocarbon such asnaphthalene, which is solid at room temperature, in the solution of theconducting organic polymer.

As described above, in cases when the protonic acid is a mineral acidsuch as sulfuric acid, hydrochloric acid, nitric acid, etc., the dopedpolymers are difficult to dissolve in an organic solvent. However, evenin the case when the polymer solution has been added, for example, intoa diluting solvent containing sulfuric acid, and the polymer has beenprecipitated, a uniform mixture in the micro-suspension state can beobtained by subjecting the mixture containing the precipitate toultrasonic wave stirring. Such a mixture can form a conducting polymerthin film on a substrate, similarly as in the case of the solution, bycoating it on a substrate and by removing the solvent.

As to the above-described second feature, since the undoping of thepolymer doped with a protonic acid used is a kind of neutralizationreaction, the undoping agent is not especially limited, as long as it isa basic substance capable of neutralizing the protonic acid as a dopant.Aqueous ammonia, and metal hydroxides such as sodium hydroxide,potassium hydroxide, lithium hydroxide, magnesium hydroxide, calciumhydroxide, etc., are preferably used for this purpose. For the undoping,a basic substance is directly added into the reaction mixture after theabove-described oxidative polymerization of aniline, or a basicsubstance may be applied after once separating out the polymer alone.

Although the polymer in the doped state, which has been obtained by theoxidative polymerization of aniline has, in general, a conductivity ofmore than 10⁻⁵ S/cm and is colored blackish green, it has a copper colormixed with violet, or faintly mixed with violet color after doping. Thischange in color is due to the change of the amine nitrogen in the saltstructure in the polymer into free amine. The conductivity of thisundoped polymer is, in general, in the order of 10⁻¹⁰ S/cm.

The thus obtained aniline oxidative polymer in the undoped state has ahigh molecular weight, and moreover, is soluble in various organicsolvents. Such a solvent includes, for example, N-methyl-2-pyrrolidone,N,N-dimethyl formamide, dimethyl sulfoxide,1,3-dimethyl-2-imidazolidinone, sulfolan, etc. As to the solubility,although it depends on the average molecular weight of the polymer andthe solvent, 0.5 to 100% of the polymer dissolves in a solvent, and asolution of 1 to 30% by weight can be obtained. In particular, theaniline oxidative polymer in the undoped state according to the presentinvention shows high solubility in N-methyl-2-pyrrolidone, and, ingeneral, 20 to 100% of the polymer dissolves to enable obtaining asolution of 3 to 30% by weight. But, it does not dissolve intotetrahydrofuran, 80% acetic acid aqueous solution, 60% formic acidaqueous solution, acetonitrile, etc.

Therefore, according to the present invention, such a polymer soluble ina solvent can be made into a film by dissolving it in the solvent andforming it into a film by the casting method. For example, a uniform andstrong free-standing film having excellent flexibility can be obtainedby a process of casting the polymer solution on a glass plate into afilm. The film thus obtained is heated and dried to remove the solvent.

In order to obtain a strong film having excellent flexibility, it isdesirable to use the above-described solvent soluble polymer having anintrinsic viscosity η! of more than 0.40 dl/g.

Further, the film obtained by casting the above-described solventsoluble aniline oxidative polymer has different properties depending onthe conditions of drying the solvent. In general, in the case of castingan N-methyl-2-pyrrolidone solution of the soluble polymer having theintrinsic viscosity η! of more than 0.40 dl/g on a glass plate anddrying to remove the solvent, if the drying temperature is less than100° C., the strength of the film obtained is not yet sufficientlylarge, and also, it partly dissolves in N-methyl-2-pyrrolidone. However,when the drying temperature is higher than 130° C., the obtained filmhas an excellent flexibility, is very strong, and is not broken evenupon bending. Also, the film obtained in such a manner does not dissolvein N-methyl-2-pyrrolidone, and furthermore, does not dissolve inconcentrated sulfuric acid. The solvent insolubility of the polymercaused by the solvent drying at a high temperature after casting isconsidered to be due to the cross-linking of polymer chains by thecoupling of radicals present in the polymer, or formed in heating.

The above-described soluble aniline oxidative polymer can be considered,from the results of measurements such as the elemental analysis,infrared absorption spectrum, ESR spectrum, laser Raman spectrum,thermogravimetric analysis, solubility in solvents, and visual or nearinfrared ray absorption spectrum, as a polymer having, as the mainrepeating unit, a compound represented by the general formula: ##STR3##wherein, m and n, respectively, show the molar fraction ofquinonediimine structural unit and phenylenediamine structural unit inthe repeating unit, and 0<m<1, 0<n<1, and m+n=1; and the organic polymeris soluble in an organic solvent in the undoped state, and has anintrinsic viscosity (η) of more than 0.4 dl/g measured inN-methyl-2-pyrrolidone at 30° C.

The film obtained by making the above-described solvent soluble polymerinsoluble in a solvent by the casting method also shows an infrared rayabsorption spectrum substantially the same as that of the solventsoluble polymer, and can be considered to have a cross-linked structurebut to consist of substantially the same repeating units from theresults of measurements on the elemental analysis, infrared absorptionspectrum, ESR spectrum, laser Raman spectrum, thermogravimetricanalysis, solubility in a solvent, visible or near infrared spectrum,etc.

In the solvent soluble polymer shown by the above-described generalformula, the values m and n can be adjusted by oxidizing or reducing thepolymer. That is, by reducing it, m is decreased and n is increased. Onthe contrary, by oxidizing it, m is increased and n is decreased. Whenthe quinonediimine structural unit in the polymer is decreased, thesolubility of the polymer into the solvent is enhanced. Also, incomparison with the state before reduction, the viscosity of thesolution is lowered.

In order to reduce such a solvent soluble polymer, hydrazines such ashydrazine hydrate, phenyl hydrazine, etc., metal hydrides such aslithium aluminum hydride, lithium borohydride, etc., and hydrogen or thelike are preferably used. Phenylhydrazine is most preferably used sinceit dissolves in an organic solvent, and in particular, inN-methyl-2-pyrrolidone, but does not reduce N-methyl-2-pyrrolidone. Onthe other hand, the oxidizing agent used in order to oxidize thesolvent-soluble polymer may be any of the ones capable of oxidizing thephenylenediamine structural unit in the general formula, but theoxidizing agent having the standard electrode potential of more than 0.3V, determined as the electromotive power in the reduction half-cellreaction standardized on the standard hydrogen electrode, is especiallypreferred. For example, as a mild oxidizing agent, silver oxide ispreferred. The blowing in of oxygen is also useful. As a powerfuloxidizing agent, potassium permanganate, potassium dichromate, etc., canalso be used, but in the use thereof, it is necessary not to deterioratethe polymer.

As described above, since the partial reduction of the solvent-solublepolymer decreases the viscosity of the polymer solution, it is useful inpreserving the solution of the solvent-soluble polymer stable in theabove-described doped state.

Also, for example, a basic substance such as triethylamine is useful forrelaxing the interaction between the protonic acid and polymer, topreserve the stable solution state.

Therefore, according to the present invention, it is possible, by addingthe above-described reducing agent and a basic substance as additives tothe solution containing the conducting organic polymer of the dopedstate and a protonic acid, to preserve the above-described solution in astable form. As described above, when the solution of the conductingorganic polymer containing reducing agent and basic substance togetherwith protonic acid is coated on a substrate, since these reducing agentsand basic substances are also evaporated at the time of removal of thesolvent, a layer of conducting organic polymer doped with protonic acidis formed on the substrate. Although the excess protonic acid willremain on the substrate, it can be removed by washing with water, ifnecessary.

Also, according to the present invention, the solution containing theconducting organic polymer in the doped state and a protonic acid mayinclude various resins functioning as a binder, as an increasing agent.The resin used as a binder is not especially limited, as long as it isone capable of dissolving in a solvent.

In the reduction of the above-described polymer, in cases when an excessamount of the reducing agent has been used, since many of thequinonediimine structural units in the polymer are reduced, theformation of semiquinone radicals (polaron structure), due to the dopingof the protonic acid to the quinonediimine structural units, areinhibited. Therefore, the conductivity of the conducting organic polymerobtained is not so high at the moment immediately after the doping.However, by leaving the doped polymer standing in air, the reducedphenylenediamine structural units gradually return back to thequinonediimine structural units, and form semiquinone radicals by beingdoped with the residual protonic acid in the polymer layer, so that anorganic polymer having a high conductivity can be obtained.

The surface resistance of the conducting organic polymer thin film is,in general, in the order of 10⁵ to 10¹⁰ Ω/□, although it is differentdepending on the protonic acid used.

Below, explanation will be given on the feature of the organic polymeraccording to the present invention obtained from the laser Ramanspectrum, by comparing it with that of the so-called polyanilinehitherto known.

In general, as the means for obtaining information relating to thevibration between atoms constituting a substance, there is known thevibration spectroscopy, which includes the infrared spectroscopy andRaman spectroscopy. The infrared spectroscopy is useful in detecting thevibrational modes causing the change of the dipole moment, and the Ramanspectroscopy is useful in detecting the vibration causing the change ofthe polarizability. Therefore, both techniques are in a complementaryrelationship, and, in general, the vibrational mode appearing strong inthe infrared spectroscopy appears weak in the Raman spectroscopy. On theother hand, the vibrational mode appearing strong in the Ramanspectroscopy, appears weak in the infrared spectroscopy.

The infrared absorption spectrum is obtained by detecting the energyabsorption between the vibrational energy levels, and the Raman spectrumis obtained by detecting the scattering light (Raman scattering)generated in dropping to a higher vibrational energy level of the groundstate after the molecule has been excited with the irradiation of light.At this time, the vibrational energy level can be known from the energydifference of the scattering light and the irradiated light.

In general, the Raman spectrum is obtained by the visible lightexcitation from an argon laser, or the like. Here, it is known that avery strong Raman line is obtained, in such a case that the sample hasan absorption band in the visible region, when the irradiated laser beamand the absorption band thereof matches. This phenomenon is known as theresonance Raman effect. According to this effect, Raman lines strongerthan 10⁴ to 10⁵ times of the usual Raman lines are obtained. By means ofsuch a resonance Raman effect, the information regarding the chemicalstructure of the molecule part excited by the wavelength of theirradiated laser beam is obtained by being more emphasized. Therefore,by measuring the Raman spectrum while changing the wavelength of thelaser beam, the chemical structure of the sample can be more exactlyanalyzed. Such a feature as described above is the feature of the Ramanspectroscopy, which cannot be found in the infrared spectroscopy.

FIG. 1 shows the laser Raman spectrum obtained by the irradiation at theexciting wavelength of 457.9 nm of the sample formed in a disk-likeshape of the powder of the polyaniline in the undoped state, which issoluble in an organic solvent, and has the intrinsic viscosity η! of 1.2dl/g measured at 30° C. in N-methyl-2-pyrrolidone. The assignment-of theRaman lines are as follows: the lines 1622 and 1591 cm⁻¹ are assigned tothe ring stretching vibration of para-substituted benzene, lines 1489and 1479 cm⁻¹ are assigned to the stretching vibration of C═C and C═N ofthe quinonediimine structure, line 1220 cm⁻¹ is assigned to the mixedexistence of C-N stretching vibration and C--C stretching vibration, andlines 1185 and 1165 cm⁻¹ are assigned to the in-plane bending vibrationof C--H.

FIG. 2 shows the laser Raman spectrum obtained by irradiating at anexciting wavelength of 457.9 nm to polyaniline in the undoped stateshown in Y. Furukawa et al., Synth. Met., 16, 189 (1986). Thispolyaniline was obtained by the electrochemical oxidative polymerizationof aniline on a platinum electrode.

As can be seen in FIG. 1, in the polyaniline in the solvent solubleundoped state according to the present invention, the ratio Ia/Ib of theRaman line strength Ia of the ring stretching vibration appearing at thewave number higher than 1600 cm⁻¹ and the Raman line strength Ib of thering stretching vibration appearing at the wave number lower than 1600cm⁻¹ is more than 1.0. In contrast to this, the hitherto knownpolyaniline including the polyaniline shown in FIG. 2, including the onemade by chemical oxidative polymerization, all have the above-describedratio Ia/Ib of smaller than 1.0.

Both of the Raman lines 1622 and 1591 cm⁻¹ are based on the ringstretching vibration of para-substituted benzene. Since the polyanilinein the reduced state has no quinonediimine structure, the Raman lineappears at 1621 cm⁻¹ only, but in the polyaniline in the undoped statehaving the quinonediimine structure, Raman lines appear at 1622 and 1591cm⁻¹ as described above. These Raman lines show the exciting wavelengthdependency as shown in FIG. 3.

Accompanying to the change of the exciting wavelength to the short waveside such as from 488.0 nm via 476.5 nm to 457.9 nm, the ratio Ia/Ibchanges. That is, at 488.0 nm, the ratio Ia/Ib is less than 1.0, but at457.9 nm, it is more than 1.0, and the strength of Ia/Ib is reversed.This reverse phenomenon can be explained as follows.

In FIG. 4 is shown the electronic spectrum of the solvent solublepolyaniline according to the present invention. Since the peak at 647 nmvanishes by reducing the polyaniline, it seems to be derived from thequinonediimine structure, and the peak at 334 nm seems to be derivedfrom the π--π* transition of para-substituted benzene. In FIG. 4 is alsoshown the above-described Raman exciting wavelength. Here, as to theband of the ring stretching vibration of para-substituted benzene, it isassumed that, when the exciting wavelength is changed to the short waveside such as from 488.0 nm to 457.9 nm, the resonance conditions of theresonance Raman effect of the band of 1622 cm⁻¹ becomes moreadvantageous in comparison with the band of 1591 cm⁻¹, and the change ofthe relative strength as described above is generated.

Next, in the spectra shown in FIG. 1 and in FIG. 2, the relativestrength of the Raman lines of 1591 cm⁻¹ and 1622 cm⁻¹ is differentdespite being generated by the same exciting wavelength (457.9 nm). Suchis explained as follows. Since N,N'-diphenyl-p-phenylene diamine, as amodel compound of the phenylenediamine structure, has a Raman line at1617 cm⁻¹ only, and N,N'-diphenyl-p-benzoquinonediimine, as a modelcompound of the quinonediimine structure, has Raman lines at 1568 cm⁻¹and at 1621 cm⁻¹ it is estimated that, as shown in the following (a),the para-substituted benzene ring non-conjugated to the quinonediiminestructure has the Raman line of 1622 cm⁻¹ with increased strength by theexcitation of the short wavelength light, and, as shown in (b) in thefollowing, the para-substituted benzene ring conjugated to thequinonediimine structure has the Raman lines of 1591 cm⁻¹ and 1622 cm⁻¹.##STR4##

Since the number of quinonediimine and the number of phenylenediaminecan be considered to be approximately equal from the results of theelemental analysis, in the solvent soluble polyaniline of the undopedstate according to the present invention, the structure or sequentialchain of the solvent soluble polyaniline in such an undoped state can beclassified into two alternating copolymer-like continuous chains of thequinonediimine structure and phenylenediamine structure as shown in (c),and the block copolymer-like sequence of the quinonediimine structureand phenylenediamine structure as shown in (d). In the figure, thepara-substituted benzene ring shown with an arrow mark shows the benzenering non-conjugated to quinonediimine, and in the above-describedalternating copolymer-like sequence, for example, they are two per 8monomer units, and in the block copolymer-like sequence, they are three.In the case when the sequence unit is longer, the difference of thenumbers of the quinonediimine and the non-conjugated benzene ring inboth becomes larger. It can be said that this difference appears as thedifference in the relative strength of the Raman lines of 1591 cm⁻¹ and1622 cm⁻¹. ##STR5##

Since, in the solvent soluble polyaniline according to the presentinvention, the Ia/Ib ratio in the laser Raman spectrum is more than 1.0,it seems that many benzene rings non-conjugated to quinonediiminestructures are contained in the polyaniline, and thus, it has theabove-described block copolymer-like sequence.

The organic solvent soluble properties of the polyaniline according tothe present invention can be explained by the fact that it has such ablock copolymer-like sequence. Although it is known that, in general,the imine nitrogen (--N═) in the quinonediimine structure forms hydrogenbonds with the secondary amino group nitrogen (--NH--) (Macromolecules,21, 1297 (1988)), the hydrogen bond between the secondary amino groupsis not strong.

Therefore, when polyaniline has the above-described alternatingcopolymer-like sequence, it forms a strong network of hydrogen bonds asshown in (f). The fact that the heretofore known polyaniline isinsoluble in many organic solvents seems to be caused by the formationof a strong network of such hydrogen bonds. In contrast, when thepolymer sequence is the above-described block copolymer-like sequence(such as that appearing in the solvent soluble polyaniline in theundoped state) according to the present invention, since the block chainhas different length in general, many hydrogen bonds can not be formed,even if the phenylenediamine structure part and the quinonediiminestructure part are adjacent (as can be seen in (e)), so that the solventpenetrates between the polymer chains and hydrogen bonds are generatedbetween the solvent, and the polymer is dissolved in the organicsolvent. If it is assumed that the block chains have perfectly the samelength at every part, the network of the hydrogen bonds (such asdescribed above) will be formed, but the probability of having such astructure is extremely small, and it can be neglected. ##STR6##

Further, such interaction between the chains, as described above, can beexplained from the C--H in-plane bending vibration of theabove-described laser Raman spectrum. The Raman line of 1162 cm⁻¹,assigned to the C--H in-plane bending vibration of the polyaniline inthe undoped state shown in the above-described FIG. 2, is shifted to thehigher wave number of 1181 cm⁻¹ when the polyaniline is reduced and allimine nitrogen groups are transformed into secondary amino nitrogengroups.

As described above, in the solvent soluble polyaniline according to thepresent invention, in the undoped state, there are two lines (such as1165 and 1185 cm⁻¹) as the Raman lines assigned to the C--H in-planebending vibration. The Raman line of 1185 cm⁻¹ is the one which can notbe seen in the hitherto known polyaniline in the undoped state, andshows a value nearly equal to that of the line 1181 cm⁻¹ which isassigned to the C--H in-plane bending vibration in the reduced state.

From these points of view, the solvent soluble polyaniline according tothe present invention is considered to have the block copolymer-likesequence in the undoped state, and has the atmosphere of a reducingstructure. From this fact, it is considered to have a high solubility inan organic solvent despite its high molecular weight. As describedabove, the polyaniline according to the present invention is a novelpolymer having a structural sequence different from that of the hithertoknown polyaniline.

As described above, since the oxidative polymer of aniline according tothe present invention has the quinonediimine structural unit and thephenylenediamine structural unit as the repeating units in the blockcopolymer-like sequence, it is explained in such a manner that, in thedoped state with a protonic acid, it has conductivity as a result of theacid-base reaction only, without an accompanying oxidation reductionreaction. This conductivity mechanism was recognized by A. G. MacDiarmidet al. (A. G. McDiarmid et al., J. Chem. Soc., Chem. Commun., 1987,1784). The quinonediimine structure is protonized by the doping with theprotonic acid to take a semi-quinone cation radical structure which hasconductivity. Such a state is called a polaron state. ##STR7##

As described above, the polyaniline which is solvent soluble in theundoped state according to the present invention can be dissolved in anorganic solvent, and can be formed into a free-standing film by thecasting method, and a composite film can be also obtained by making thesolution into a film by the casting method on an appropriate substrate,and by doping such a film with a protonic acid, a conductive film isreadily given. Here, the protonic acids described above may be used.

Before doping, the reflected light from the film exhibits copper colorand the transmitted light blue color. But, after doping with protonicacid, the reflected light exhibits a blue color, and the transmittedlight a green color. Also, after doping, the reflectance of the nearinfrared region (1000 to 2000 nm) changes to a large extent. That is,before doping, almost all the infrared rays are reflected, but afterdoping, almost all of the infrared rays are absorbed.

The conductivity of the conductive film obtained by doping depends onthe pKa value of the protonic acid used. For the doping of the oxidativepolymer of aniline, the protonic acid having the pKa value of less than4.8 is effective, and when the protonic acid having the pKa value of 1to 4.8 is used, the smaller the pKa value thereof is, that is, thestronger the acidity is, the higher the conductivity of the filmobtained is. However, when the pKa value is less than 1, theconductivity of the film obtained changes little and is approximatelyconstant. However, if necessary, a protonic acid having the pKa value ofless than 1 may be used.

In such a manner as described above, the conductivity of the conductivefilm according to the present invention, and obtained by doping of aprotonic acid, is, in general, more than 10⁻⁵ S/cm, and in many cases,more than 10⁻⁴ S/cm. Accordingly, the conductive film according to thepresent invention is solely, or as a composite film, very useful, forexample, as an anti-electrostatic material such as described in thefollowing.

This conducting film according to the present invention is strong, anddoes not easily break, even if it is bent. However, since thisconducting film is doped with a protonic acid, in the same way as in theconducting polymer prepared under the existence of a protonic acid, itis insoluble in the above-described organic solvent, due to theabove-described reason, or owing to the cross-linking by the coupling ofthe radicals formed in the heat and evaporation process of the solventin the time of film preparation.

According to the present invention, a conducting film in which theundoping is especially difficult can be obtained by using polyvinylsulfonic acid as the protonic acid.

In general, the polyaniline obtained by oxidative polymerization isdoped with the protonic acid used in the time of polymerization.However, it is known that such a conducting polyaniline releases theprotonic acid as a dopant in a weakly acidic, neutral, or alkalineaqueous solution, or in a basic organic solvent to remarkably lower itsconductivity.

Further, since the protonic acid generally used heretofore as a dopantis a low molecular acid, such as hydrochloric acid, sulfuric acid,perchloric acid, etc., when a polyaniline thin film having such a lowmolecular acid as a dopant was used, for example, as ananti-electrostatic material, the low molecular acid is apt to bediffused to cause concern for corroding the metal part of thecircumference.

However, in the conducting polyaniline having polyvinyl sulfonic acid asa dopant according to the present invention, the lowering of itsconductivity is remarkably small in an aqueous solution of more than pH2.5, or especially in the nearly neutral one, in comparison with notonly the above-described polyaniline with a low molecular acid as adopant, but also with the polyaniline having polymer acids such aspolystyrene sulfonic acid, polyallyl sulfonic acid, polyvinyl sulfuricacid, etc., as a dopant.

The reason why the lowering of the conductivity of the polyanilinehaving polyvinyl sulfonic acid as a dopant is remarkably small is notnecessarily clear, but it is considered to be due to the polymer effectof the polyvinyl sulfonic acid being a polymer acid having a polyvalentcharge and also to the molecular structure effect of the polyvinylsulfonic acid mutually acting strong with polyaniline in the molecularlevel.

In order to dope the polyaniline in the undoped state with polyvinylsulfonic acid, the above-described polyaniline is immersed in an aqueoussolution of polyvinyl sulfonic acid at a pH of less than 2. Although thetime required for doping depends on the film thickness of thepolyaniline film used and the pH of the polyvinyl sulfonic acid aqueoussolution, in general, it may be as long as several tens of seconds toseveral days. In order to shorten the doping time, it is preferable thatan aqueous solution of pH of less than 1 is used. Further, in general,when a polyvinyl sulfonic acid having a low polymerization degree isused, doping can be effected rapidly, and on the other hand, when thepolyvinyl sulfonic acid having a high polymerization degree is used, aconducting polyaniline film, in which undoping is more difficult, can beobtained.

In such a manner as described above, since in the polyaniline havingpolyvinyl sulfonic acid as a dopant it is difficult to release thedopant in a weakly acidic, neutral, or alkaline aqueous solution, itsconductivity is not changed in the various procedures in the time ofproduction of the conducting polyaniline film, even by washing withwater and an organic solvent, and a conducting film can beadvantageously produced.

Further, since a conducting film that does not contain another protonicacid such as, for example, the above-described low molecular acid as adopant can be obtained, for example, by washing with water sufficiently,after doping the polyaniline with polyvinyl sulfonic acid, such aconducting film will not corrode the metal parts in the circumference ofthe apparatus by the low molecular acid which might be partly mixed as adopant in the conducting polyaniline. Also, when the conductingpolyaniline is used in water and in an organic solvent, the conductivityis preserved for a long period. Therefore, such a conductive film asthis can be used with high reliability, and preferably as an electricand electronic material such as the anti-electrostatic material,electromagnetic wave shielding material, etc.

According to the present invention, by utilizing the coating propertiesof the above-described solvent soluble aniline oxidative polymersolution, other than the organic polymer film, composite bodies producedby making the surfaces of various articles conductive can be obtained.

Such a composite body as described above can be obtained by coating thesolution of the above-described oxidative polymer of aniline soluble inan organic solvent on a substrate, and after making a thin film, thefilm is doped with a protonic acid. Here, the substrate is notespecially limited, but for example, such materials as the filmscomprising various resins, molded products, foamed bodies, fibers,cloths, non-woven cloths comprising glass or resins, plate, foil, fibre,structured bodies consisting of metals, etc. may be used. A preferredexample of such a composite body is a conductive composite film made bycoating the solution of the above-described oxidative polymer of anilinesoluble in an organic solvent on a substrate made of a polyimide film orpolyester film to form a thin film, and subsequently, by doping the filmwith a protonic acid.

In particular, according to the present invention, since the coatingprocedure on the substrate and the doping procedure of the solventsoluble polyaniline can be effected separately, continuous production ofsuch a conductive composite film is easily carried out. Also, accordingto the present invention, since the solvent soluble polyaniline can bemade into a film by casting and coating, a thin film having a very thinfilm thickness and high transparency can be obtained on the substrate.For example, after continuously forming a thin film with film thicknessof 0.01 to 0.5 μm on a transparent substrate film such as that made ofpolyethylene terephthalate, the film can be rolled-up. Further, byadjusting the thickness of the thin film, the surface resistance can becontrolled in various ways. Such a composite body can be preferably usedas an anti-electrostatic composite body. In particular, by making thethickness of the thin film about 0.01 to 0.5 μm, the composite filmobtains visual light transmissivity of 80% or more, and ananti-electrostatic film having the surface resistance of about 10⁴ to10¹¹ Ω/□ can be obtained.

Also, by using the conductive composite film thus obtained having theanti-electrostatic function, and by adding thereto a release agent layerand an adhesive agent layer, a pressure-sensitive adhesive tape withoutbeing peeling charged in the time of winding back of the tape can beobtained. As the release agent, ordinary ones such as siliconecompounds, long chain alkyl compounds, etc., may be used, and as theadhesive agent, acrylic compounds, rubber compounds, etc., may be used.

According to the present invention, although the ordinary method can beused in forming a film or a thin film on a substrate such as, forexample, a polyethylene terephthalate film or a polyimide film bycasting the solvent soluble polyaniline, it is preferable that thesolvent soluble polyaniline is casted on the substrate while heating thesubstrate to evaporate off the solvent. By such a method, the wettingproperties of the substrate are enhanced, the spring-off of thepolyaniline solution on the substrate is prevented, and the polyanilinesolution can be uniformly coated. Thus, a uniform polyaniline thin filmcan be easily obtained. It is preferable that the substrate is heated tosuch an extent that its surface temperature is from 80° to 120° C., orpreferably, in the range of 90° to 100° C.

Also, according to the present invention, in the case when a solventsoluble polyaniline is casted to form a film or a thin film, a uniformpolyethylene thin film can be easily obtained by first subjecting thesubstrate to sputter etching, in a range where the discharge treatmentamount is defined as the product of the treating power density and thetreating time is 0.1 to 50 W second/cm², or preferably, in the range of1 to 30 W second/cm². The solvent soluble polyaniline is then cast onthe surface of such a substrate, and then the solvent is evaporated off.In particular, this method is preferable when a fluorine resin film isused as the substrate.

The sputter etching treatment is effected, in general, at roomtemperature. The frequency of the high frequency power used may be overthe range of several hundred KHz to several ten MHz, but in practice, itis preferable that 13.56 MHz, which is the industrial allotmentfrequency, is used. The distance between the electrodes is determined tobe proportional to the reciprocal number of the square root of theatmospheric pressure, as for example, when the atmospheric pressure is0.005 Torr, as more than 30 mm. Although air and steam are generallyused as the atmosphere, other than those, inert gases such as nitrogen,argon, helium, etc., and carbon dioxide gas, etc., are used. On thesubstrate subjected to the sputter etching treatment as described above,for example, on the surface of a fluorine resin molded product, areformed active polar groups such as the carboxyl group, aldehyde group,hydroxide group, etc., and the wetting properties for an organic solventare remarkably improved.

Heretofore, as the means for improving the wetting properties of thefluorine resin molded products such as films, membranes, etc., varioustechniques are known such as corona discharge, plasma treatment,chemical treatment, etc., but by means of these treatments, the wettingproperties of the surface of the fluorine resin molded product to thepolyaniline solution is almost not improved. However, as describedabove, by first letting the surface of the fluorine resin product besubjected to the sputter etching treatment, or by improving the wettingproperties of the surface of the fluorine resin molded product to thepolyaniline solution, the polyaniline solution can be uniformly coatedon the surface of the fluorine resin molded product, and thus, a uniformpolyaniline thin film can be obtained on the surface of a fluorine resinmolded product.

The sputter etching treatment is described, for example, in the officialpublication of Japanese Patent Application No. 22108/1978, etc., and isalready well-known as a treatment for applying high frequency voltagebetween the negative and positive electrodes under a reduced pressure ina pressure resistive vessel, to accelerate positive ions formed bydischarge and let them collide with the surface of the molded product onthe negative electrode. The equipment for this treatment is constitutedas such that the negative electrode and the positive electrode arearranged in the pressure resistive vessel in a counterposed manner, andthe negative electrode is connected to the high frequency power sourcevia an impedance adjustor, and the positive electrode is connected tothe earth side of the high frequency power source. In the outside of thenegative electrode is arranged a shield electrode, and is kept at theearth potential. The molded products can be treated in any of the batchsystem and the continuous system depending on the conditions of theequipment. Such equipment includes, for example, the equipment describedin the official publication of Japanese Patent Application No.1337/1981, and No. 1338/1981 etc.

Further, from the above-described solvent soluble aniline oxidativepolymer according to the present invention, a heat-proof fibre can beobtained by extruding its solution from a spinning nozzle, and byremoving the solvent therefrom by heating and drying, and when it isdoped with a protonic acid a conducting fibre can be obtained.

As described above, since the aniline oxidative polymer in the undopedstate according to the present invention dissolves well in varioussolvents, and especially in N-methyl-2-pyrrolidone, and has a far highermolecular weight in comparison with the hitherto known polyaniline, astrong film having excellent flexibility and heat-proof properties,which is not broken even if bent, is easily obtained by the castingmethod. Also, it can be made into a film or a thin film on anappropriate substrate.

Moreover, by doping such a film or a thin film with a protonic acid, ahigh conducting organic polymer with high strength can be obtained inthe same manner. This conducting film has high stability, and can beused, for example, as an anti-electrostatic material and anelectromagnetic wave shielding material.

Also, the solvent soluble polymer according to the present invention canbe spun into a fibre, and when this is doped, a conducting fibre can beobtained.

Further, the aniline oxidative polymer according to the presentinvention is soluble in an organic solvent even in a doped state, whenit has been doped with an organic acid having the acid dissociationconstant pKa value of less than 4.8, or with a certain kind of inorganicacid. Therefore, such a solution can immediately form a thin film of theconducting organic polymer on a substrate by coating it on a suitablesubstrate, and by removing the solvent.

EXAMPLES

Although the present invention will be explained by referring to thefollowing examples, the present invention is not limited in any way bythese examples.

Example 1

(Production of the conducting organic polymer in a doped state by theoxidative polymerization of aniline)

In a separable flask of 10 l volume, equipped with a stirrer, athermometer and a straight tube adapter, is put 6000 g of distilledwater, 360 ml of 36% hydrochloric acid, 400 g (4.295 mol) of aniline inthis order, and the aniline was dissolved. Separately, to 1493 g ofdistilled water was added 34 g (4.295 mol) of 97% concentrated sulfuricacid, and mixed to prepare a sulfuric acid aqueous solution. Thissulfuric acid aqueous solution was added into the above-describedseparable flask, and the whole flask was cooled to -4° C. in a lowtemperature thermostat.

Next, 980 g (4.295 mol) of ammonium peroxodisulfate was added to 2293 gof distilled water in a beaker, and were dissolved to prepare anoxidizing agent aqueous solution.

The whole flask was cooled in a low temperature thermostat, and whilepreserving the temperature of the reaction mixture below -3° C., theabove-described ammonium peroxodisulfate aqueous solution was graduallydropped from the straight tube adapter into an acidic solution of ananiline salt at a rate of 1 ml/min by use of a tubing pump. At first,the colorless transparent solution changed its color in accordance withthe progress of polymerization, from greenish blue to blackish green,and successively, a blackish green colored powder separated out.

Although temperature rise was detected in the reaction mixture in thetime of this powder precipitation, in order to obtain the high molecularweight polymer in this case also, it is important to maintain thetemperature in the reaction system at less than 0° C., or preferablybelow -3° C. After the precipitation of the powder, the dropping rate ofthe ammonium peroxodisulfate aqueous solution may be slightly hastened,such as, for example, to about 8 ml/min. However, in this case also, itis necessary to adjust the dropping rate such as to preserve thetemperature below -3° C., while monitoring the temperature of thereaction mixture. Thus, after finishing the dropping of the ammoniumperoxodisulfate aqueous solution by spending 7 hours, stirring wascontinued for an additional hour at the temperature of below -3° C.

The polymer powder obtained was filtered off, washed with water andcleaned with acetone, and dried in vacuum at room temperature to obtain430 g of blackish green colored polymer powder. This powder was pressedto mold a disk of the size of the diameter of 13 mm, thickness of 700μm, and its conductivity was measured by the Van der Pauw method toobtain the value of 14 S/cm.

(Undoping of a conducting organic polymer with ammonia)

Into 4 l of a 2N ammoniacal water was added 350 g of the above-describeddoped conducting organic powder, and the mixture was stirred in anautohomomixer at the rotation number of 5000 r.p.m. for 5 hours. Thecolor of the mixture changed from blackish green to bluish violet.

The powder was filtered off with a Buchner funnel, and while beingstirred in a beaker, was repeatedly washed with distilled water untilthe filtrate became neutral, and successively was washed with acetoneuntil the filtrate became colorless. Afterwards, the powder was vacuumdried at room temperature for 10 hours to obtain a blackish browncolored undoped polymer powder of 280 g.

This polymer was soluble in N-methyl-2-pyrrolidone, and its solubilitywas 8 g (7.4%) for 100 g of the same solvent. Also, the intrinsicviscosity η! measured at 30° C. by using the same liquid as a solventwas 1.23 dl/g.

The solubility of this polymer in dimethylsulfoxide anddimethylformamide was less than 1%. In tetrahydrofuran, pyridine, 80%acetic acid aqueous solution, 60% formic acid aqueous solution, andacetonitrile, the polymer was substantially insoluble.

The laser Raman spectrum obtained by irradiating the beam at theexciting wavelength of 457.9 nm to a sample formed of the powder ofpolyaniline in the undoped state and molded in a disk-like shape isshown in FIG. 1. For comparison's sake, the laser Raman spectrumobtained by irradiating the beam at the exciting wavelength of 457.9 nmon the polyaniline of the undoped state, and shown in Y. Furukawa etal., Synth. Met., 16, 189 (1986) is shown in FIG. 2. This polyanilinehad been the one obtained by the electrochemical oxidativepolymerization of aniline on a platinum electrode.

Also, the result of the measurement of Raman spectrum in the range of1400 to 1700 cm⁻¹ by changing the wavelength of the laser exciting beamis shown in FIG. 3. Accompanying the change of the exciting wavelengthfrom 488.0 nm to 476.5 nm to the short wave side, the ratio Ia/Ibchanged, and at 457.9 nm, it became more than 1.0, and in comparisonwith the case of 488.0 nm, it was seen that the strength ratio Ia/Ib wasreversed.

Further, an electronic spectrum is shown in FIG. 4.

Next, the GPC measurement was carried out on the above-described organicsolvent soluble polyaniline by using the GPC column for use with theN-methyl-2-pyrrolidone. As the column, the one made by connecting threekinds of columns for use with N-methyl-2-pyrrolidone was used. Also, asthe eluent, the N-methyl-2-pyrrolidone solution of lithium bromide at aconcentration of 0.01 mol/l was used as an eluent. The result of the GPCmeasurement is shown in FIG. 5.

From this result, it was found that the above-described organic solventsoluble polyaniline had the number-averaged molecular weight of 23,000and the weight-averaged molecular weight of 160,000 (both values areconverted to the polystyrene standard).

In the same manner, solvent soluble polyanilines having differentintrinsic viscosities η! measured at 30° C. in N-methyl-2-pyrrolidonewere obtained by changing reaction conditions in various ways. Theintrinsic viscosity η! and the number-averaged molecular weight and theweight-averaged molecular weight are shown in Table 1.

                  TABLE 1                                                         ______________________________________                                        Intrinsic                                                                     viscosity   Molecular weight by GPC                                            n!         Number-averaged                                                                           Weight-averaged                                        dl/g!      molecular weight                                                                          molecular weight                                      ______________________________________                                        0.40        10000        48000                                                0.48        12000       120000                                                0.56        14000       130000                                                0.76        18000       140000                                                1.23        23000       160000                                                ______________________________________                                    

Example 2

(Preparation of a free standing film by use of a soluble anilineoxidative polymer)

Five grams of the undoped aniline oxidative polymer obtained in Example1 were added into 95 g of N-methyl-2-pyrrolidone in each small amount,and was dissolved at room temperature to obtain a blackish-blue coloredsolution. This solution was vacuum filtered with a G3 glass filter toobtain the insoluble matter residue on the filter in an extremely smallamount. This filter was washed with acetone, and after drying theresidual insoluble matter, the weight of the insoluble matter wasmeasured to be 75 mg. Therefore, the soluble part of the polymer was98.5%, and the insoluble matter was 1.5%.

The polymer solution obtained in such a manner as described above wascasted on a glass plate by means of a glass rod, and theN-methyl-2-pyrrolidone was evaporated off in a hot wind circulatingdrier at 160° C. for two hours. Subsequently, by immersing the glassplate in cold water, the polymer film was peeled off naturally, andthus, a polymer film of the thickness of 40 μm was obtained.

After cleaning this film with acetone, it was wind dried at roomtemperature to obtain a copper colored film having a metallic lustre.

The strength and solubility of the film are different depending on thedrying temperature thereof. When the drying temperature was below 100°C., the film obtained dissolves in N-dimethyl-2-pyrrolidone in a smallamount, and together with that, its strength is also comparativelysmall. But, the film obtained by heating at a temperature above 130° C.was very strong, and also did not dissolve into a solvent such asN-methyl-2-pyrrolidone. Also, it did not solve in a concentratedsulfuric acid. It seems that the polymer molecules mutually bridge toeach other and become insoluble during the procedure of such heating asdescribed above.

The conductivity of the films in the undoped state and obtained thus wasin either case in the order of 10⁻¹¹ S/cm.

Also, the film was not broken even if bent for 10,000 times, and itstensile strength was 850 kg/cm².

Example 3

(Doping of the free standing film with a protonic acid)

After immersing the free standing films obtained in Example 2 in 1Nsulfuric acid, perchloric acid, and hydrochloric acid aqueous solution,respectively, at room temperature for 66 hours, they were cleaned withacetone and wind dried to obtain a conducting film, respectively.

All films exhibited a concentrated blue color, and the conductivity was,respectively, 9 S/cm, 13 S/cm, and 6 S/cm. Also, the tensile strength ofthe film doped with perchloric acid was 520 kg/cm².

Example 4

(The spectrum and structure of the soluble polymer and the polymer madeinto an insoluble film, which are both in the undoped state)

The FT-IR spectra of the powder of the soluble polymer obtained inExample 1 and the insoluble polymer film obtained in Example 2 measuredby the KBr method are shown respectively in FIG. 6 and FIG. 7. In thespectrum of the insoluble polymer film obtained in Example 2, theabsorption at 1660 cm⁻¹ due to the solvent residue,N-methyl-2-pyrrolidone, is a little detected, but since the two spectraare almost the same, it is perceived that there is no large changeproduced in the chemical structure, although the polymer is made to besolvent insoluble due to the bridging by the heating and drying of thesolvent after the casting of the solvent soluble polymer.

The result of thermogravimetric analysis of the above-described solublepolymer powder and the insoluble film is shown in FIG. 8. Both have highheat resistant properties. Since the insoluble film is not decomposeduntil up to a higher temperature, and when it is considered that it isinsoluble in a concentrated sulfuric acid, it is due to the fact thatthe polymer molecules are bridged.

Also, the ESR spectrum is shown in FIG. 9. The spin concentration is1.2×10¹⁸ spin/g in the soluble polymer, and as the heating temperatureis increased, the spin concentration becomes higher, which shows thatradicals are formed by the heating. It seems that the polymer is bridgeddue to the coupling of the radicals and the heated film becomesinsoluble.

Next, the results of elemental analysis on the soluble polymer andinsoluble polymer will be shown in the following.

Soluble polymer

C, 77.19; H, 4.76; N, 14.86 (total 96.81)

Insoluble polymer

C, 78.34; H, 4.99; N, 15.16 (total 98.49)

On the basis of this elemental analysis, the composition formula of thesoluble polymer normalized at C12.00 is C₁₂.00 H₈.82 N₁.98, and thecomposition formula of the insoluble polymer is C₁₂.00 H₉.11 N₁.99. Onthe other hand, the quinonediimine structural unit and thephenylenediamine structural unit normalized at C 12.00 in the samemanner are respectively as follows.

quinonediimine structural unit C₁₂ H₈ N₂

Phenylenediamine structural unit C₁₂ H₁₀ N₃

Accordingly, both the soluble polymer and the solvent insoluble polymerare, as described above, the polymers having the quinonediiminestructural unit and phenylenediamine structural unit as the mainrepeating units.

Next, the reflective spectra in the visual to near infrared region ofthe film of undoped state obtained in Example 2 and the film doped withperchloric acid are respectively shown in FIG. 10. In the undoped statealmost all the near infrared rays are reflected, but after doping, thenear infrared rays are absorbed, and it is noted that there is almost noreflection. This is based on the absorption due to the polaron or thehiper polaron which brings about the conductivity formed by the dopingof a protonic acid.

Also, by carrying out the doping of the film in the undoped state withperchloric acid, the ESR absorption is increased to a large extent andthe spin concentration reaches even up to 3.8×10²¹ spin/g. This is dueto the semi-quinone radical as the polaron formed.

Example 5

The polymer films obtained in Example 2 were immersed in protonic acidaqueous solutions or alcoholic solutions having various pKa values toexamine the advisability of the doping. The conductivity of polymerfilms obtained by doping protonic acids having various pKa values areshown in Table 2. It is shown that the protonic acids having pKa valuesof less than 4.8 are effective for the doping of the polymer.

                  TABLE 2                                                         ______________________________________                                                                   Conductivity                                       Dopant             pKa     (S/cm)                                             ______________________________________                                        Hydrochloric acid.sup.a)                                                                         0.47    6                                                  p-Toluene sulphonic acid.sup.a)                                                                  (0.7).sup.d)                                                                          3.1                                                Oxalic acid.sup.b) 1.23    1.9                                                Dichloroacetic acid.sup.a)                                                                       1.48    0.5                                                Malonic acid.sup.a)                                                                              2.78    1.4                                                Monochloroacetic acid.sup.a)                                                                     2.85    1.7 × 10.sup.-2                              Malic acid.sup.a)  3.4     8.5 × 10.sup.-2                              p-Nitro-benzoic acid.sup.b)                                                                      3.46    3.7 × 10.sup.-4                              Formic acid.sup.c) 3.75    2.1 × 10.sup.-2                              Acrylic acid.sup.c)                                                                              4.25    4.8 × 10.sup.-2                              Acetic acid.sup.c) 4.75    3.7 × 10.sup.-2                              Propionic acid.sup.c)                                                                            4.88    .sup. 4.1 × 10.sup.-11                       ______________________________________                                         Note:                                                                         .sup.a) Doping with 1N aqueous solution                                       .sup.b) Doping with 1N alcoholic solution                                     .sup.c) Doping with 100% solution (solventless)                               .sup.d) The value of benzenesulfonic acid                                

Example 6

(Production of transparent conducting thin film composite body)

An N-methyl-2-pyrrolidone solution of 0.5% by weight of the solublepolymer powder obtained in Example 1 was prepared, and after it wascoated on a polyethylene terephthalate film of the thickness of 75 μm,the film was dried at 150° C. for 1 hour. After doping the film obtainedby immersing it in a 1N perchloric acid aqueous solution for 3 hours, itwas washed with acetone and wind dried.

The composite film was cut in squares, and a silver paste was coated onthe two peripheral sides mutually counterposed, and the surfaceresistance was measured to get the value of 3.5M/cm². Also, theconductivity was 0.02 S/cm. As a result of observation of the sectionalsurface of this composite film using transmissive type electronmicroscope photography, the thickness of the aniline oxidative polymerfilm was found to be about 0.1 μm.

Also, the surface resistance of this film changed little even in avacuum, or under the low humidity of the globe box replaced with argon(dew point of -37° C., humidity 180 ppm).

Example 7

(Production of a conductive organic polymer of the de-doped state by theoxidative polymerization of aniline)

Into a separable flask of 1l volume, equipped with a stirrer, athermometer, and a dropping funnel, were put 450 g of distilled water,30 ml of 6% hydrochloric acid, and 30 g (0.322 mol) of aniline in thisorder, and the aniline was dissolved. Separately, 32 g of a 97%concentrated sulfuric acid (0.32 mol) were added to the 112 g ofdistilled water in the beaker while cooling with ice water, and themixture was mixed to prepare a sulfuric acid aqueous solution. Thissulfuric acid aqueous solution was added into the above-describedseparable flask, and the whole flask was cooled down to the temperatureof less than 5° C. with ice water.

Next, 73.5 g (0.322 mol) of ammonium peroxodisulfate was added todistilled water in a beaker, and was dissolved to prepare an oxidizingagent aqueous solution.

The whole flask was cooled in a low temperature thermostat, and whilepreserving the temperature of the reaction mixture below -3° C., theabove-described ammonium peroxodisulfate aqueous solution was graduallydropped onto the aqueous solution of the aniline salt under stirringexpending 105 minutes. At first, the colorless transparent solutionchanged its color from greenish blue to blackish green, andsuccessively, blackish green colored powder was separated. Afterfinishing the dropping of the ammonium peroxodisulfate aqueous solution,stirring was continued for 45 minutes at the temperature of -3° C.

A part of the polymer powder obtained was washed with water and acetone,and was vacuum dried at room temperature, and a blackish green polymerpowder was obtained. The powder was pressed to form a disk of the sizeof diameter of 13 mm, and the thickness of 700 μm, the conductivity ofwhich was measured to obtain the value of 18 S/cm.

(Undoping of the conducting organic polymer by use of ammonia)

To the reaction mixture containing the above-described doped conductingorganic polymer powder in a flask was added 150 ml of 25% ammoniacalwater, and was stirred under cooling for 1.5 hours. The color of thereaction mixture changed from blackish green to bluish violet.

The powder was filtered through a Buchner funnel, and while stirring ina beaker, was repeatedly washed with distilled water until the filtratebecame neutral, and successively, was washed with acetone until thefiltrate became colorless. Afterwards, the powder was vacuum dried atroom temperature for 10 hours to obtain 22.5 g of violet colored undopedpolymer powder.

This polymer was soluble in N-methyl-2-pyrrolidone, and its solubilitywas 8 g (7.4%) to 100 g of the same solvent. Also, its intrinsicviscosity η! measured at 30° C. by use of the same solvent was 1.20.

The solubility of this polymer in dimethylsulfoxide anddimethylformamide was less than 1%.

The polymer was not substantially soluble in tetrahydrofuran, pyridine,80% acetic acid aqueous solution, 60% formic acid aqueous solution, andacetonitrile.

Example 8

(Preparation of the free-standing film by use of the soluble anilineoxidative polymer)

Five grams of undoped aniline oxidative polymer powder obtained inExample 7 was very gradually added into 950 g of N-methyl-2-pyrrolidone,and was dissolved at room temperature, and a blackish blue solution wasobtained. When this solution was vacuum filtered with a G3 glass filter,the insoluble matter remaining on the filter was extremely small. Thisfilter was washed with acetone, and after drying the remaining insolublematter, its weight was measured to obtain the value of 75 mg. Therefore,98.5% of the polymer was dissolved, and the insoluble matter was 1.5%.

The polymer solution thus obtained was casted on a glass plate by use ofa glass rod, and was dried in a hot air circulating drier at 160° C. for2 hours to evaporate off N-methyl-2-pyrrolidone. Afterwards, byimmersing the glass plate in cold water, the polymer film was naturallypeeled-off and a polymer film having a thickness of 40 μm was obtained.

After washing this film with acetone, it was dried in air at roomtemperature to obtain a copper-colored film having metallic lustre.

The film shows different strength and solubility depending on the dryingtemperature thereof. When the drying temperature is less than 100° C.,the film obtained is slightly soluble in N-methyl-2-pyrrolidone, andtogether with that, its strength is comparatively small. However, thefilm obtained at a temperature higher than 130° C. is very strong, anddoes not dissolve in N-methyl-2-pyrrolidone and in other organicsolvents. Also, it does not dissolve in sulfuric acid. It seems that,when the film is heated at a high temperature, the polymer moleculescross-link to each other during the procedure, and become insoluble.

The thus obtained film, in the undoped state, had a conductivity in eachof them in the order of 10⁻¹⁰ S/cm.

Also, the film was not broken by bending even if bent 10,000 times, andits tensile strength was 840 kg/cm².

Next, results of the elemental analysis on the soluble polymer andinsoluble polymer will be shown in the following.

Soluble polymer:

C, 77.97; H, 5.05; N 14.68 (total 97.70)

Insoluble polymer:

C, 78.31; H, 5.38; N 15.31 (total 99.00)

The composition formula of the soluble polymer normalized to C 12.00 onthe basis of this elemental analysis is C₁₂.00 H₉.26 N₁.94 and that ofthe insoluble polymer is C₁₂.00 H₉.82 N₂.01. On the other hand,quinonediimine structural unit and phenylenediamine structural unitnormalized in the same way to C 12.00 are respectively as follows:

Quinonediimine structural unit C₁₂ H₃ N₂

Phenylenediamine structural unit C₁₂ H₁₀ N₂

Therefore, both the soluble polymer and solvent insoluble polymer arepolymers having quinonediimine structural units and the phenylenediaminestructural unit as the main repeating units.

Example 9

(Production of a conducting polyaniline thin film)

After preparing an N-methyl-2-pyrrolidone solution of 0.5% of thesolvent soluble polyaniline powder prepared in Example 7, and aftercoating it in a thin film-like form on a glass plate (5 cm×1 cm) by thespin coat method (1500 r.p.m. for 30 seconds), the plate was heat-driedat 150° C. for 1 hour to obtain a thin film having the thickness ofabout 300 Å.

On this thin film were formed silver paste coatings of the length of 10mm at 2 mm intervals, and a copper wire was connected to the silverpaste, and the surface resistance was measured to obtain the value of10¹³ to 10¹⁴ Ω/□.

Successively, after immersing the polyaniline thin film obtained on aglass plate in a polyvinylsulfonic acid aqueous solution of pH 1 at roomtemperature for 15 hours, it was dried at room temperature to obtain adoped conducting polyaniline thin film. The surface resistance thereofwas measured in the same manner as described above, to obtain the valueof 9.0×10⁵ Ω/□. This product was washed with distilled water of pH 6,and further immersed in distilled water for 15 hours to obtain thesurface resistance of 4.6×10⁸ Ω/□.

Also, when the conducting polyaniline thin film was washed with methanolin place of distilled water, and further immersed in methanol for 3hours, the surface resistance was 2.8×10⁸ Ω/cm².

Comparative Example 1

After immersing the pre-doped polyaniline thin film obtained in Example9 in a hydrochloric acid of pH 1 for 15 hours, it was dried at roomtemperature to obtain a doped conducting polyaniline thin film. Thesurface resistance thereof was 8.5×10⁶ Ω/□. This film was washed withdistilled water of pH 6, and when it was further immersed in distilledwater for 15 hours, the surface resistance thereof increased to 3.2×10¹⁴Ω/□.

Also, when the conducting polyaniline thin film was washed with methanolin place of distilled water, and was further immersed in methanol for 3hours, the surface resistance increased to 4.5×10¹⁴ Ω/□.

Comparative Example 2

After immersing the pre-doped polyaniline thin film obtained in Example9 in a sulfuric acid aqueous solution of pH 1 for 15 hours, it was driedat room temperature to obtain a doped conducting polyaniline thin film.The surface resistance thereof was 2.2×10⁶ Ω/□. The film was washed withdistilled water of pH 6, and when it was further immersed in distilledwater for 15 hours, the surface resistance increased to 7.6×10¹³ Ω/□.

Also, the conducting polyaniline thin film was washed with methanol inplace of distilled water, and when it was further immersed in methanolfor 3 hours, the surface resistance increased till to 3.0×10¹³ Ω/□.

Example 10

After immersing the polyaniline free-standing film obtained in Example 8in a polyvinyl sulfonic acid aqueous solution of pH 0.5 for 24 hours atroom temperature, it was dried at room temperature to obtain a dopedconducting polyaniline film. The conductivity thereof was 2.83 S/cm. Itwas refined by washing with distilled water of pH 6, and when it wasfurther immersed in distilled water for 16 hours, the conductivity was1.52 S/cm.

Comparative Example 3

After immersing the polyaniline free-standing films obtained in Example8 in various protonic acid aqueous solutions for 24 hours, it was driedat room temperature to obtain doped conducting polyaniline films. Theconductivity thereof is shown in Table 3. Also, these conducting filmswere refined by washing with distilled water of pH 6, and theconductivity thereof after further immersion in distilled water for 16hours are each shown in Table 3.

Contrary to that of the conducting film in which polyvinyl sulfonic acidwas used as a dopant, after being immersed in distilled water, theconducting film showed remarkable lowering of the conductivity.

                  TABLE 3                                                         ______________________________________                                                         Conductivity (S/cm)                                                             After                                                                         immersion                                                                     in protonic                                                                   acid aqueous                                                                             After                                           Dopant             solution   washing                                         ______________________________________                                        Example Polyvinyl sulfonic                                                                           2.83       1.52                                        10      acid                                                                  Compara-                                                                              Perchloric acid                                                                              0.53       0.004                                       tive    Trifluoroacetic acid                                                                         2.36       0.08                                        Example Hydrochloric acid                                                                            3.10       0.10                                        3       Sulfuric acid  3.43       0.13                                                1,2-Ethanedisulfonic                                                                         3.85       0.53                                                acid                                                                          Phosphoric acid                                                                              4.77       0.03                                                acid                                                                          2-Acrylamide-2-methyl-                                                                       2.3 × 10.sup.-7                                                                    6.0 × 10.sup.-10                              propane sulfonic                                                              acid                                                                          Polyphosphoric acid                                                                          0.11       0.015                                               Polyvinylsulfonic                                                                            2.55       0.24                                                acid                                                                          Polystyrenesulfonic                                                                          3.01       0.13                                                acid                                                                          Polyallylsulfonic                                                                            1.8 × 10.sup.-6                                                                    5.2 10.sup.-8                                       acid                                                                  ______________________________________                                    

Example 11

After immersing the polyaniline free-standing film obtained in Example 8in a polyvinyl sulfonic acid aqueous solution of pH 0.5 for 24 hours, itwas dried at room temperature to obtain a doped conducting polyanilinefilm. The conductivity thereof was 3.21 S/cm. The film was refined bywashing with distilled water of pH 6, and was further immersed indistilled water for 288 hours. The conductivity thereof was 0.10 S/cm.

Comparative Example 4

After immersing the polyaniline free-standing film obtained in Example 8in a hydrochloric acid aqueous solution of pH 0.5 for 24 hours, it wasdried to obtain a doped conducting polyaniline film. The conductivitythereof was 2.68 S/cm. The film was refined by washing with distilledwater of pH 6, and further, it was immersed in distilled water for 288hours. The conductivity was 0.0013 S/cm.

Comparative Example 5

After immersing the polyaniline free-standing film obtained in Example 8in a sulfuric acid aqueous solution of pH 0.5 for 24 hours, it was driedat room temperature to obtain a doped conducting polyaniline film. Theconductivity thereof was 2.32 S/cm.

The film was refined by washing with distilled water of pH 6, and wasfurther immersed in distilled water for 288 hours, the conductivitythereof was 0.020 S/cm.

Example 12

An N-methyl-2-pyrrolidone solution of 0.5% by weight of solvent solublepolyaniline obtained in Example 7 was prepared.

An aluminum plate and a glass plate were stacked up on a hot plate, anda polyethylene terephthalate film of the thickness of 80 μm was mountedthereon, and the surface temperature thereof was made to be 100° C. Onthe surface of this film was dropped the above-described polyanilinesolution, and was casted by use of an applicator. The solvent evaporatedoff rapidly from the polyaniline solution and a uniform polyaniline filmwas formed.

After heating this film at 130° C. for 1 hour, it was immersed in aperchloric acid aqueous solution and was refined by washing withacetone, and afterwards, was further dried at 130° C. for 1 hour toobtain a doped film.

This film had a thickness of 0.02 μm, a surface resistance of 1.3×10¹¹Ω/□, an optical transmittance of 87%, and a charged chargehalf-reduction period of 9.0 seconds.

Example 13

An N-methyl-2-pyrrolidone solution of 1% by weight of the solventsoluble polyaniline obtained in Example 7 was prepared.

In the same manner as in Example 12, the surface temperature of thepolyethylene terephthalate film was made as 90° C., and theabove-described polyaniline solution was dropped on the surface of thefilm to be casted by use of an applicator. The solvent was rapidlyevaporated off from the polyaniline solution, and a uniform polyanilinefilm was formed.

After heating this film at 130° C. for 1 hour, it was immersed in apolyvinylsulfonic acid aqueous solution and washed with acetone, andafterwards, it was again dried at 130° C. for 1 hour to obtain a dopedfilm.

This film had a thickness of 0.05 μm, surface resistance of 8.2×10⁸ Ω/□,light transmittance of 84%, and charged charge half-reduction period of1.3 seconds.

Example 14

An N-methyl-2-pyrrolidone solution of 3% by weight of the solventsoluble polyaniline obtained in Example 7 was prepared.

In the same manner as in Example 12, the surface temperature of thepolyethylene terephthalate film was made to be 90° C., and theabove-described polyaniline solution was dropped on the surface of thefilm to be casted by use of an applicator. The solvent rapidlyevaporated-off from the polyaniline solution, and a uniform polyanilinefilm was formed.

After heating this film at 130° C. for 1 hour, it was immersed in apolyvinylsulfonic acid aqueous solution and washed with acetone, andsubsequently, it was again dried at 130° C. for 1 hour to obtain a dopedfilm.

This film had a thickness of 0.075 μm, surface resistance of 3.5×10⁶Ω/□, light transmittance of 82%, and charged charge half-reductionperiod of 0.05 seconds.

Example 15

An N-methyl-2-pyrrolidone solution of 0.5% by weight of the solventsoluble polyaniline obtained in Example 1 was prepared.

Steam was introduced into a pressure resistant vessel under a reducedatmosphere of 1×10⁻³ Torr to make the pressure in the vessel 5×10⁻²Torr, and sputter etching treated a polyethylene terephthalate film ofthe thickness of 80 μm in such a manner that the charging treatmentamount became 3 W second/cm². When this film was immersed into water, itwas ascertained that the whole surface was wetted by water.

The above-described polyaniline solution was dropped on this film andcasted by use of an applicator to obtain a uniform film. After heatingthis film at 130° C. for 1 hour, it was immersed in a perchloric acidaqueous solution and was washed with acetone, and subsequently, the filmwas again dried at 130° C., and a doped film was obtained.

The surface resistance of this film was 3.0×10⁸ n/cm².

Example 16

An N-methyl-2-pyrrolidone solution of 2% by weight of the solventsoluble polyaniline obtained in Example 7 was prepared.

Steam was introduced into a pressure resistant vessel under a reducedatmosphere of 1×10⁻³ Torr to make the pressure in the vessel be 7×10⁻²Torr, and sputter etching treatment was carried-out on apolytetrafluoroethylene film of the thickness of 50 μm in such a mannerthat the discharge treatment amount became 20 W second/cm². When thisfilm was immersed in water, it was ascertained that the whole surfacewas wetted with water.

The above-described polyaniline solution was dropped on this film andwas casted by use of an applicator, and a uniform film was obtained.After heating this film at 130° C. for 1 hour, it was immersed in aperchloric acid aqueous solution and washed with acetone, andsubsequently, it was again dried at 130° C. for 1 hour, and a doped filmwas obtained.

The surface resistance of this film was 2.0×10⁶ Ω/□.

Example 17

An N-methyl-2-pyrrolidone solution of 2% by weight of the solventsoluble polyaniline obtained in Example 1 was prepared.

Steam was introduced into a pressure resistant vessel under the reducedpressure atmosphere of 1×10⁻³ Torr to make the pressure in the vessel be5×10⁻² Torr, and sputter etching treatment was carried out on thetetrafluoroethylenehexafluoro propylene copolymer film in such a mannerthat the discharge treatment amount became 10 W second/cm².

When this film was immersed in water, it was ascertained that the wholesurface was wetted with water.

The above-described polyaniline solution was dropped on this film andwas casted by use of an applicator, and a uniform film was obtained.After heating this film at 130° C. for 1 hour, it was immersed in aperchloric acid aqueous solution and was washed with acetone, andsubsequently, it was again dried at 130° C. for 1 hour to obtain a dopedfilm.

The surface resistance of this film was 5.0×10⁵ Ω/□.

Example 18

After casting an N-methyl-2-pyrrolidone solution of 1% by weight of thesolvent soluble polyaniline obtained in Example 7 on a polyethyleneterephthalate film of the thickness of 80 μm by use of an applicator,the film was heat dried at 130° C., and a polyaniline film of thethickness of 0.15 μm was obtained.

This film was immersed in a perchloric acid aqueous solution for 30seconds, and after washing the film with acetone, it was again dried at130° C. for 1 hour, and a doped film was obtained.

On these compound films, the close adhesive properties, surfacehardness, friction wear strength, light transmittance, conductivity andfriction charging properties of conducting polyaniline thin films areshown in Table 4.

                                      TABLE 4                                     __________________________________________________________________________                  Example 18                                                                          Example 19                                                                           Example 20                                                                          Example 21                                                                          Comparable Example                     __________________________________________________________________________                                           6                                      Close adhesive properties                                                                   100   100    100   --    100                                    Pencil hardness                                                                             3H to 4H                                                                            3H to 4H                                                                             3H to 4H                                                                            --    3H to 4H                               Light transmittance (%, 640 nm)                                                             84    88     82    --    70                                     Wearing properties                                                                          2.7% uprise                                                                         2.3% low down                                                                        2.4% uprise                                                                         --    6.9% uprise                            Conductivity (S/cm, 24° C.,                                                          1.1 × 10-4                                                                    7.1 × 10.sup.-7                                                                4.2 × 10.sup.-4                                                               3.7 × 10.sup.-1                                                               2.5 × 10.sup.-10                 50% RH)                                                                       Friction charging properties (V)                                                            -20   +1000  -20   -4    +7000                                  __________________________________________________________________________

The test methods for determining the above-described physical propertieswere as follows:

Close adherence properties:

Checkerboard squares were cut on the sample composite film by use of acutter knife, and a cellophane tape (18 mm width) was pasted thereon,and the tape was peeled-off after 3 minutes, and the residual number ofmeasures in 100 measures was evaluated.

Surface hardness:

Pencil hardness (according to JIS K 5401) was adopted. A pencilscratching test material was used, and the evaluation was made by seeingwhether the occurrence of flaws was found under a load of 200 g.

Wear strength:

A reciprocal motion wear test machine was used. After shaving thesurface for 30 cycles with a grinding paper sheet of #2000, whileapplying a load of 200 g thereon, the change of light transmittance(wavelength 800 nm) was examined.

Light transmittance:

The transmittance in the wavelength range (visible light) of 400 to 800nm was measured.

Conductivity:

The four terminal method was adopted.

Friction charge properties:

After strongly rubbing the surface with a gauze 10 times, the chargedvoltage was measured.

Example 19

In the same manner as in Example 18, a conducting polyaniline filmhaving a thickness of 0.15 μm was formed on thepolyethyleneterephthalate film, and a composite film was obtained.

The properties of this composite film are shown in Table 4.

Example 20

After casting the N-methyl-2-pyrrolidone solution containing 5% byweight of the solvent soluble polyaniline obtained in Example 7 on apolyethyleneterephthalate film having a thickness of 80 μm by use of anapplicator, the product was heat-dried at 130° C. to obtain apolyaniline film having a thickness of 0.3 μm.

After immersing this film in a hydrofluoroboric acid aqueous solutionand washed with acetone, it was dried at 150° C. for 1 hour to obtain adoped film.

On this composite film, the close adherence properties of the conductingpolyaniline thin film, surface hardness, wear resistance, lighttransmittance, conductivity and friction charging properties weremeasured, and the results are shown in Table 4.

Example 21

In the same manner as in Example 18 except that a propylene non-wovencloth was used as a substrate, a conducting composite body was obtained.On this composite body, conductivity and friction charging propertieswere measured, and the results are shown in Table 4.

Comparative Example 6

After casting the N-methyl-2-pyrrolidone solution of 1% by weight of thesolvent soluble polyaniline obtained in Example 7 on a polyethyleneterephthalate film with thickness of 80 μm by use of an applicator, theproduct was heat-dried at 130° C. to obtain a polyaniline film withthickness of 0.15 μm.

On the composite film with no doping to the film thereafter, the closeadhesive properties of the polyaniline thin film, surface hardness, wearstrength, light transmittance, conductivity, and friction chargingproperties were measured, and the results are shown in Table 4.

Example 22

The solvent-soluble polyaniline of the undoped state obtained in Example1 was dissolved in N-methyl-2-pyrrolidone (NMP) together with theprotonic acid shown in Table 5 and with an additive, as needed, toprepare a solution.

This solution was coated on a polyethylene terephthalate film by meansof the kissroll coat method, and heat-dried in a hot wind dryer furnaceat 100° C. The surface resistance value of the conducting polyanilinethin film obtained is shown in Table 5. As in the case of experimentalnumber 6, the film thickness of the conducting polyaniline thin filmobtained was about 0.08 μm as determined by the observation of thesectional surface by means of the ultrathin film slice method using thetransmission type electron microscope.

Example 23

The powder (0.5 g) of the solvent-soluble polyaniline in the undopedstate was added with stirring into 99.5 g of N-methyl-2-pyrrolidone todissolve, and a solution of the concentration of 0.5% by weight wasprepared.

Separately, as shown in Table 6, a dopant was added to a dilutingsolvent, and was dissolved. Other than isopropanol, as the dilutingsolvent, acetonitrile, ethylacetate, or tetrahydrofuran was used. Also,other than malonic acid, as the dopant, dichloroacetic acid,terephthalic acid, or sulfuric acid was used. Furthermore, sinceterephthalic acid does not dissolve in the diluting solvent,isopropanol, it was previously dissolved in an N-methyl-2-pyrrolidonesolution. As an additive, naphthalene was used.

The dopant (and additive) solution obtained was added to theabove-described polymer solution, and was diluted. All of the solutionobtained here did not absorb humidity and was stable for a long period.

Successively, this solution was coated on a polyethyleneterephthalatefilm by means of the kissroll coat method, and was heat-dried in a hotair dryer furnace at 100° C. The film thickness and surface resistancevalue of the conducting polyaniline thin film obtained are shown inTable 6.

In cases when sulfuric acid is used as a dopant, the doped polyanilineprecipitates. However, by subjecting the mixture containing theprecipitate to ultrasonic wave stirring, a uniform solution can beobtained, and by coating this solution on a substrate and evaporatingthe solvent, a thin film of the conductive organic polymer can be formedon a substrate.

Measurement of the Surface Resistance Value

The sample obtained was cut in 40×40 mm, and two electrodes werearranged in parallel on a thin film of the conducting organic polymerwhile keeping gaps of 10 mm between them, using a conductive graphitepaint to be dried at room temperature. Next, on the graphite-coated filmof the sample was attached a golden galvanized clip which was connectedto a digital high tester No. 3116 made by Hioki Electric Machine Co.,Ltd., and the resistance value was measured. The value obtained wasmultiplied 4 times, and the obtained value was taken as the surfaceresistance.

                                      TABLE 5                                     __________________________________________________________________________    Polyaniline solution composition (% by weight)                                Polyaniline                                                                         Dopant             Additive    NMP                                                                              surface resistance                    __________________________________________________________________________    0.5   malonic acid     1.0           98.5                                                                             1.1 × 10.sup.6                                                          (Ω/□)                0.5   salicylic acid   1.3           98.2                                                                             1.7 × 10.sup.10                 1.0   polyacrylic acid (25% aqueous soln.)                                                           5.5           93.5                                                                             5.0 × 10.sup.10                 0.5   pentadecafluorooctanic acid                                                                    1.1           98.4                                                                             3.5 × 10.sup.6                  0.5   1-dodecansulfonic acid (10% aq. soln)                                                          3.5           96.0                                                                             3.8 × 10.sup.4                  1.0   p-toluenesulfonic acid monohydrate                                                             1.1           97.9                                                                             2.2 × 10.sup.6                  0.5   polystyrenesulfonic acid                                                                         triethylamine                                                                          0.15                                                                             94.95                                                                            8.3 × 10.sup.7                        aq. soln. (pH 0.5)                                                                             4.4                                                    0.5   polyvinylsulfonic acid                                                                           triethylamine                                                                          0.15                                                                             94.95                                                                            2.2 × 10.sup.9                        aq. soln. (pH 0.5)                                                                             4.4                                                    0.5   malonic acid     1.0                                                                             polyvinyl chloride.sup.a)                                                              0.5                                                                              98 4.3 × 10.sup.6                  0.5   malonic acid     1.0                                                                             Bylon.sup.b)                                                                           0.5                                                                              98 5.7 × 10.sup.6                  1.0   p-toluenesulfonic acid monohydrate                                                             1.1                                                                             polyvinyl chloride.sup.a)                                                              1.0                                                                              96.9                                                                             6.8 × 10.sup.6                  1.0   p-toluenesulfonic acid monohydrate                                                             1.1                                                                             Bylon.sup.b)                                                                           1.0                                                                              96.9                                                                             2.8 × 10.sup.6                  1.0   p-toluenesulfonic acid monohydrate                                                             1.1                                                                             phenylhydrazine                                                                        0.3                                                                              97.6                                                                             7.2 × 10.sup.6                  __________________________________________________________________________     (Note)                                                                        .sup.a) Sumilitt (trade mark) SX8G made by Sumitomo Chemical Industry Co.     Ltd.                                                                          .sup.b) Bylon200 (saturated polyester resin made by Toyobo Co., Ltd      

                                      TABLE 6                                     __________________________________________________________________________    Composition.sup.b) of diluting solution                                                                 Conducting organic polymer thin film                Polymer concentration.sup.a)                                                             N-methyl-2-                      film surface resist-              (weight %) pyrrolidone                                                                         Diluting solvent                                                                       naphthalene                                                                         dopant      thickness                                                                          tance (Ω/.quadratur                                                     e.)                          __________________________________________________________________________    0.05       100   isopropanol 900                                                                        --    malonic acid 200                                                                          0.072 μm                                                                        1.5 10.sup.7                 0.25       100   isopropanol 100                                                                        --    malonic acid 200                                                                          0.090                                                                              3.7 10.sup.4                 0.125      100   isopropanol 300                                                                        --    malonic acid 200                                                                          0.087                                                                              2.1 10.sup.5                 0.083      100   isopropanol 500                                                                        --    malonic acid 200                                                                          0.085                                                                              3.7 10.sup.5                 0.05       100   isopropanol 900                                                                        0.5   malonic acid 200                                                                          0.073                                                                              1.0 10.sup.7                 0.05       100   acetonitrile 900                                                                       0.5   malonic acid 200                                                                          0.046                                                                              8.8 10.sup.8                 0.05       100   ethylacetate 900                                                                       0.5   malonic acid 200                                                                          0.038                                                                              3.0 10.sup.9                 0.05       100   tetrahydrofuran 900                                                                    0.5   malonic acid 200                                                                          0.038                                                                              2.9 10.sup.9                 0.05       100   isopropanol 900                                                                        --    malonic acid 100                                                                          0.068                                                                              7.0 10.sup.7                 0.05       100   isopropanol 900                                                                        --    dichloroacetic acid 100                                                                   0.040                                                                              2.8 10.sup.9                 0.05       100   isopropanol 900                                                                        --    terephthalic acid 100                                                                     0.035                                                                              4.3 10.sup.9                 0.05       100   isopropanol 900                                                                        --    sulfuric acid 50                                                                          0.042                                                                              2.3 10.sup.9                 0.05       100   isopropanol 900                                                                        --    sulfuric acid 25                                                                          0.033                                                                              5.2 10.sup.9                 1.0        100   --       --    p-toluenesulfonic acid 105                                                                0.088                                                                              2.7 10.sup.5                 __________________________________________________________________________     (Note)                                                                        .sup.a) The 1.0% solution was prepared as itself, and a dopant was            dissolved in it, and the other ones were at first a 0.5% solution was         prepared, which was diluted with the diluting solvent.                        .sup.b) The composition is represented in weight parts for                    Nmethyl-2-pyrrolidone, diluting solvent, and naphthalene, and for dopants     in the number of weight parts per 100 weight parts of polyaniline.       

While the invention has been described in detail and with reference tospecific embodiments thereof, it will be apparent to one skilled in theart that various changes and modifications can be made therein withoutdeparting from the spirit and scope of the invention.

What is claimed is:
 1. A method for producing a conducting organicpolymer film, characterized by dissolving an organic polymer in anorganic solvent, casting the solution obtained, evaporating off theorganic solvent to obtain an organic polymer film, and doping with aprotonic acid having a pKa value of less than 4.8; wherein the organicpolymer has, as the main repeating unit, a compound represented by thegeneral formula: ##STR8## wherein, m and n respectively show the molarfraction of the quinonediimine structural unit and the phenylenediaminestructural unit in the repeating unit, and 0<m<1, 0<n<1, and m+n=1; andsaid organic polymer has an intrinsic viscosity η! of more than 0.48dl/g measured in N-methyl-2-pyrrolidone at 30° C., and has, in theundoped state, a ratio Ia/Ib of the intensity of the Raman line Ia ofthe ring stretching vibration appearing at a wave number higher than1600 cm⁻¹ and the intensity of the Raman line Ib of the ring stretchingvibration appearing at a wave number lower than 1600 cm⁻¹ in the ringstretching vibration of para-substituted benzene in the laser Ramanspectrum obtained by exciting with a light of wavelength of 457.9 nmmore than 1.0; wherein the organic polymer is obtained by adding 2 to2.5 equivalents amounts of an aqueous solution of an oxidizing agent permole of aniline in the presence of a protonic acid.
 2. A method forproducing a conducting organic polymer fiber, characterized bydissolving an organic polymer into an organic solvent, spinning thesolution obtained, evaporating off the organic solvent to form anorganic polymer fiber, and doping this fiber with a protonic acid havinga pKa value of less than 4.8; wherein the organic polymer has, as themain repeating unit, a compound represented by the general formula:##STR9## wherein, m and n respectively show the molar fraction of thequinonediimine structural unit and the phenylenediamine structural unitin the repeating unit, and 0<m<1, 0<n<1, and m+n=1; and said organicpolymer has an intrinsic viscosity η! of more than 0.48 dl/g measured inN-methyl-2-pyrrolidone at 30° C., and has, in the undoped state, a ratioIa/Ib of the intensity of the Raman line Ia of the ring stretchingvibration appearing at a wave number higher than 1600 cm⁻¹ and theintensity of the Raman line Ib of the ring stretching vibrationappearing at a wave number lower than 1600 cm⁻¹ in the ring stretchingvibration of para-substituted benzene in the laser Raman spectrumobtained by exciting with a light of wavelength of 457.9 nm more than1.0; wherein the organic polymer is obtained by adding 2 to 2.5equivalents amounts of an aqueous solution of an oxidizing agent permole of aniline in the presence of a protonic acid.
 3. A method forproducing a conducting organic polymer film, characterized by dissolvingan organic polymer in an organic solvent, casting the obtained solution,evaporating off the organic solvent to obtain an organic polymer film,and doping the film with a protonic acid having a pKa value of less than4.8; wherein the organic polymer has, as the main repeating unit, acompound represented by the general formula: ##STR10## wherein, m and nrespectively show the molar fraction of the quinonediimine structuralunit and phenylenediamine structural unit in the repeating unit, and0<m<1, 0<n<1, and m+n=1; and said organic polymer is soluble in anorganic solvent in the undoped state, has an intrinsic viscosity η! ofmore than 0.48 dl/g measured in N-methyl-2-pyrrolidone at 30° C., and,in the undoped state, has a ratio Ia/Ib of the intensity of the Ramanline Ia of the ring stretching vibration appearing at the wave numberhigher than 1600 cm⁻¹ and the intensity of the Raman line Ib of the ringstretching vibration appearing at the wave number lower than 1600 cm⁻¹in the ring stretching vibration of para-substituted benzene in thelaser Raman spectrum obtained by exciting with a light of wavelength of457.9 nm more than 1.0; wherein the organic polymer is obtained byadding 2 to 2.5 equivalents amounts of an aqueous solution of anoxidizing agent per mole of aniline in the presence of a protonic acid.4. A method for producing a conducting organic polymer fiber,characterized by dissolving an organic polymer in an organic solvent,spinning the solution obtained, evaporating off the organic solvent toform a conducting organic polymer fiber, and doping the fiber with aprotonic acid having a pKa value less than 4.8; wherein the organicpolymer has, as the main repeating unit, a compound represented by thegeneral formula: ##STR11## wherein, m and n respectively show the molarfraction of the quinonediimine structural unit and the phenylenediaminestructural unit in the repeating unit, and 0<m<1, 0<n<1, and m+n=1; andthe organic polymer is soluble in an organic solvent in the undopedstate, has an intrinsic viscosity η! of more than 0.48 dl/g measured inN-methyl-2-pyrrolidone at 30° C., and has, in the undoped state, a ratioIa/Ib of the intensity of the Raman line Ia of the ring stretchingvibration appearing at the wave number higher than 1600 cm⁻¹ and theintensity of the Raman line Ib of the ring stretching vibrationappearing at the wave number lower than 1600 cm⁻¹ in the ring stretchingvibration of para-substituted benzene in the laser Raman spectrumobtained by exciting with a light of wavelength of 457.9 nm more than1.0; wherein the organic polymer is obtained by adding 2 to 2.5equivalents amounts of an aqueous solution of an oxidizing agent permole of aniline in the presence of a protonic acid.